1. Field of the Invention
The present invention relates to an optical disk drive and a method of controlling a spindle motor thereof. More particularly, the present invention relates to an optical disk drive and a method thereof for controlling a spindle motor to adaptively stop the spindle motor rotation according to the varying level of a detected tracking error signal.
2. Description of the Related Art
An optical disk drive, which records data on an optical disk or reproduces recorded data, usually includes, in addition to other components, a spindle motor. The spindle motor rotates the optical disk mounted on a tray at a predetermined speed, and is typically a brushless motor which provides a detected RPM (Revolutions Per Minute) value using a hole sensor.
FIG. 1 is a block diagram illustrating such a conventional optical disk drive.
Referring to FIG. 1, an optical disk drive 100 includes a spindle motor 110, a motor driver 120, and a motor controller 130.
The motor driver 120 supplies a predetermined driving voltage to drive the spindle motor 110.
When supplied with the predetermined driving voltage from the motor driver 120, the spindle motor 110 is rotated clockwise or counter-clockwise at a speed corresponding to the driving voltage, and an optical disk 110a is rotated in a direction corresponding to the rotation of the spindle motor 110.
When a brushless motor having a hole sensor (not shown) is used as the spindle motor 110, the spindle motor 110 is provided with a frequency generator (FG) 112. The FG 112 generates a pulse form FG signal corresponding to an RPM of the spindle motor 110 detected by the hole sensor (not shown). The FG signal is then transmitted to the motor controller 130.
The motor controller 130 counts the number of pulses of the FG signal transmitted from the spindle motor 110 for a predetermined time to detect the RPM of the spindle motor 110. Based on the detected RPM, the motor controller 130 controls the operation of the motor driver 120. For example, in order to stop the rotation of the spindle motor 110, the motor controller 130 controls the motor driver 120 to supply the spindle motor 110 with a brake driving voltage corresponding to the detected RPM as based on the number of pluses of the FG signal. As the spindle motor 110 is supplied with the brake driving voltage, the spindle motor 110 completely stops rotation.
However, since the conventional optical disk drive 100 uses brushless motor technologies to control the operation of the spindle motor 110, the optical disk drive 100 is required to employ the hole sensor (not shown) to generate the FG signal corresponding to the RPM of the spindle motor 110. Accordingly, manufacturing costs increase and it is exceedingly difficult to achieve the desired size and simplicity required by such a product.
Also, in the conventional optical disk drive 100, a tray (not shown) can be unintentionally opened during the rotation of the optical disk 100a when a user stops the reproduction of the optical disk 100a. Therefore, physical damage can occur in the optical disk, sometimes resulting in reproduction failures of the optical disk 100a. 
Accordingly, a need exists for a system and method to safely control an optical disk drive spindle motor, such as a DC motor, without requiring any additional costly devices such as a hole sensor.